The breadcrumbs for the above would be [Automotive][Make][Year][Color][Drive][Effeciency]. The user can move from one item to the other, because the link will be assigned in the router. So, when the Make is clicked, the controller Automotive will be instantiated and the method Make will get executed. The initial selections are stored in session so that the user can hop around.

The controller would be the Automotive and the methods connected to the model are